This invention relates to the orientation of effusive material structures within a cathode ray tube and more particularly to a device for retentively positioning an effusive structure within a cathode ray tube envelope.
It is conventional practice in cathode ray tubes of the type employed in television display applications, to position a container of effusive material, such as for example a getter, on the terminal portion of the electron generating assembly oriented within the neck portion of the tube envelope. An exemplary effusive structure of this type is one referenced within the art as an antenna getter, such being usually comprised of a resilient longitudinal supporting member or curved wand having a container of gettering material terminally mounted thereon. Upon insertion and orientation of the electron gun assembly within the neck portion, the forward extending getter container is positioned closely adjacent to the interior surface of the outwardly flared funnel portion of the tube envelope which is usually coated with an electrical conductive material. During process activation of getters so positioned, the effusive material emanating therefrom is deposited over a broad area of the funnel-disposed conductive coating.
In certain types of tube constructions, two or more diverse electrically related coatings are disposed in discrete areas of the funnel portion. In such instances, the dispersal of a broad area of gettering material thereover becomes a deleterious factor in that it effects electrical leakage between the conductive areas. While diffusion directive means have been fashioned and incorporated with the getter containers to control the effusion of material emanating therefrom, there are times when adequate and consistent control is difficult to achieve especially when the getter is positioned proximal to the diversely coated areas.
In another orientation, gettering means have been mounted in the forward region of the tube envelope on screen related structures, such as shadow masks or electrode members, prior to sealing of the face panel to the funnel portion of the envelope, since there was no means for installation of the getter after consummation of the panel-funnel seal. This prior-to-sealing positioning of directional getter means evidences disadvantages in that heat required for sealing of the panel to the funnel is of a temperature adversely affecting the gettering material.